Variability of glenoid labral tear patterns: a study of 280 sequential surgical cases.

Abstract

Glenoid labrum tears are a common cause of shoulder pain and instability and tear patterns have historically been ascribed into categorical descriptions such as anterior, posterior, and superior labral tears (SLAP [superior labrum anterior and posterior]) with multiple subtypes. Although often quoted as representing no more than 10% of instabilities, posterior shoulder instability may be more common than previously recognized. The purpose of this study was to review observed labral tear patterns and compare incidence and morphologies to historical descriptions. All patients undergoing arthroscopic or open labral repair (Current Procedural Terminology codes 29806, 29807, 23455, 23460, 23462, 23465) by 2 fellowship-trained shoulder surgeons from July 2012 to May 2019 were retrospectively reviewed. Labral tears were categorized into 3 groups: exclusively anterior to the midline of the glenoid, exclusively posterior, and those crossing the midline of the glenoid. Chief complaint, mechanism of injury, hand dominance, preoperative MRI interpretation by surgeon, and independent radiologist were analyzed for each tear type. During the 7-year period, 280 patients underwent arthroscopic or open labral repair. Sixty percent of tears were traumatic, with dislocation being the most common traumatic mechanism at 31.4%. Ten distinct tear patterns were identified: 3 types of 90° tears (anteroinferior, posteroinferior, and posterosuperior), 4 types of 180° tears (anterior, posterior, inferior, and SLAP), 2 types of 270° tears (anteroinferior and anterosuperior), and 360° labral tears. A total of 134 tears (47.9%) were classified as posterior, and 72 tears (25.7%) were anterior. Seventy-four tears (26.4%) were combined anterior-posterior tears. Labral tears involving some portion of the posterior labrum constituted 74% of tears. A significant association between tear location and primary complaint (P < .001) was noted. Patients with anterior tears complained of only instability in 62.5% of cases, and only pain in 22%. Patients with posterior labral tears complained primarily of pain in 68% of cases, and instability in 21%. There was an accurate preoperative diagnosis given by both radiologists and surgeons on 30% (n = 63) of the tears. There is a wide variety of labral tear patterns identified at the time of surgery, and the incidence of posterior labral tears is higher than previously described. Isolated Bankart lesions are relatively rare and are often associated with more extensive labral lesions. Patients with posterior labral pathology more often complain of pain rather than instability, whereas patients with anterior labral tears more often complain of instability.